Abrasion resistance testing apparatus for insulated wire



April 10, 1945. GRAVES 2,373,115

ABRASION RESISTANCE TESTING APPARATUS FOR INSULATED WIRE Filed Feb. 26, 1944 2 sheets-sheet 1 [NVENTOR I-LKEI' BVEE ATTORNEY April 10, 1945. H. K. GRAVES ABRASION RESISTANCE TESTING APPARATUS FOR INSULATED WIRE 2 Sheets-Sheet 2 Filed Feb. 26, 1944 ATTORNEY Patented Apr. 10, 1945 UNITED STATES PATENT} OFFICE ABRASI ON RESISTANCE TESTING APPA- RAT US FOR INSULATED WIRE Harold K. Graves, Tenafly, N. J. Application February 26, 1944, Serial No. 524,133 Claims. (Cl. 73-7) (Granted under the act oi March 3, 1883, as f a amended April 30, 1 938; 370 0. G; 757) In the handling. or processing of insulated wires, various conditions may arise, such asthe passage thereof around sharp corners'or the like, when the wire is being uncoiled from a storage reel and rewound, for example, on an armature coil. As an exposure of the wire through breakage of the insulation will give rise to short circuiting of the-electrical system in which it may ultimately be placed, it is imperative that the insulation possess to a high degree an abrasion resistant quality in order to prevent its failure when subjected to the ordinary fabricating processes.

This invention, therefore, relates to a method and apparatus for testing the abrasion resistance qualities of various types and grades oi coatings applied to wire and the'like and, in particular,

' to the insulating coatings applied to magnet wire.

It is an object of this invention to provide a method and apparatus for rapidly and effectively determining the abrasion resistance qualities of magnet wire insulation,

Another object of this invention is to provide an apparatus by which a continually increasing concentrated force may be applied to a freshly presented surfa'c'e of the wire insulation under investigation until failure thereof occurs.

Still a further object of this invention is to provide a variable speed apparatus for determining the abrasion resistance qualities of the insulation coating of wire. i

' These and other objects as well as the various tested is connected to double pole switch Hi and other novel features and advantages of this invention will become apparent from a reading of the following specification and accompanying drawings of which:

Fig. 1 is a plan view of the wire insulation abrasion resistance testing apparatus;

Fig. 2 is a side elevation view thereof ;-and Fig. 3 is a sectional view taken at 3-3 of Fig. 1. With referenceto Figs. 1, 2'and 3, the testing apparatus consists of a frame ll having secured thereto a. magnet wire supply unit l2, pressure.

applying unit l3, insulation abrasion resistance testing unit, i4, insulation breakdown indicating unit l3, secured to frame If, comprises an upright support 25 to which ispivotally mounted a graduated bar 26 on which is secured a slidable weight 21, a' pressure roller 28, an adjustable tension spring 29 and an additional load applying support 3|. Magnet wire supply unit I! consists of a drum 3: provided with a hand crank 33 Y and adjustable brake 34, andguide pulley 35 and stepped pulley 35 supported in suitable pedestals 31 and 38 respectively.

Unit l4 consists of a supply drum -39, with a supply oi piano wire "of a diameter of 0.015

inches coiled thereon to be utilized as an insula tion abrasion element as hereinafter defined, mounted on a pedestal 42 and provided with an adjustable brake 4|, a hardened steel apertured guide 43, piano wire take-up drum 44 and supporting pedestal 50, worm gear unit 45 actuated by a chain drive 4521 connected to a sprocket on the gear reduction unit I 9 and worm supporting pedestal 46.

Secured to the power output shaft of the speed gear drive reduction unit I9 is a stepped pulley 41 and to the power input shaft a pulley 48 driven by motor 2| through belt 49. Lamp is provided for indicating' a, failure of the wire insulation being to a'suitable source of electrical supply not shown. One of the terminals of' lamp I5 is secured to a slip 'ring of supply drum 32 and the other terminal to hardened sheel guide 43.

In order to prepare theapparatus for carrying out a test of the abrasion resistance qualities of the insulation of a given sample of magnet wire 5|, one end of the wire is connected to drum 32, so that an electrical bond to the slip ring is provided, and a supply of wire wrapped thereon by actuating hand crank 33, and the other end of the wire threaded through the testing apparatus by passing the wire over guide pulley 35, through the .hardened steel guide 43 but abov and at right angles to abrasion wire 40 which has previously been threaded through the apertured lamp I5 and double pole switch it, slack take-up I weights I! and I8, speed reduction unit I8 and variable speed electric motor 2| connected through double pole switch It, as is the lamp [5,

to a suitable source of electrical supply notshown. Frame l I, to which the various elements are attached, is made up of lower and upper bases 22 and 23 respectively, secured together in spaced relationship by means of stanchions 24 mounted 21 is secured to a suitable'cord 53 guide 43 and properly tensioned, passed once arounddriving pulley 41, over guide pulley 36 and secured to a take-up weight I1. slidable weight which is passed over guide pulley 54, once around stepped drivingpulley 41, over stepped guide pulley 36 and secured to the slack take-up weight 18. Brake 34 is then adjusted to provide the desired tension at the comers thereof. The pressure applying 55 to be imposed upon the magnet wire 5| when it is drawn through the apparatus. The tensioning force imposed is proportional to the cross-sectional area of the wir so that for a wire of 0.0453

inch in diameter a pull of 6 poundsis preferred.

The insulation abrasion resistance test is carried out in the following manner:

asvaiic Double pole switch It is snapped to the on position, thus energizing electric motor 2| so that itis broughtup to the speed desired to cause the magnet wire to travel "at approximately 12 feet per minute, the slidable weight 21 at such a speed as to cause the loading at pressure roller 28 to increase at'a rate of 3 pounds per minute, and the piano wire 40 to move'at a linear speed of approximately $4, foot per minute. As the bar 26 is calibrated to indicate the force in pounds applied to the roller 28, the position of slidable weight 21 thereon, as it moves thereover, is carefully checked and its position noted at the instant lamp l5 flashes. Thus the abrasive force necessary to cause a break through of the in- 'sulationv and resultant closure of the lamp electrical circuit by exposure of the wire 5! is readily ascertained. Should it be desirable to apply a force greater than that ultimately obtainable by the slidable weight 21 alone, an initial loading on pressure roller 28 may be obtained by placing weights on the support 3| before' the test is begun.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of the invention 'and that various changesin construce tion, proportion and arrangement of the parts may be made within the scope of the appended claims without sacrificing any of the advantagesof the invention.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. A wire insulation abrasion resistance testing a A wire insulation abrasion resistance testing apparatus comprising 'an insulation abrading means adapted to presentcontinuously a fresh abrading surface, speed adjustable wire engaging means for drawing at a predetermined speed a sample of insulated wire across said abrading suring wire is passed'at a predetermined tension and speed, speed adjustable wire engaging means for drawing at a predetermined speed a sample of insulated wire to be tested through said guide at right angles to and across said insulation abrading wire, adjustable braking means for opposing 'movement of said wire sample thereover, calibrated progressively increasing pressure applying means adapted to press said wire sample against said insulation abrading wire, and means indicating the instant at which failure of the insulation of said test sample wire occurs.

6. A wire insulation abrasion resistance testing apparatus comprising a base upon which are mounted a reel for storing a'supply of insulated wire to be tested, an adjustable brake for said reel, a hardened steel guide, a driven stepped pulley adapted to engage and draw said insulated wire throughsaid guide, a slack take-up weight for said wire, -variable speed means for driving I said pulley, a reelon which is coiled a length of apparatus comprising a wire abrading means,

variable speed wire engaging means for drawing a sample of insulated wire across said abrading means, adjustable braking means for opposing movement of said wire thereover, calibrated power driven progressively increasing pressure applyingmeans adapted to press said wire against said abrading means, and means indicating the hardened steel wire, an adjustable brake: for said reel, a driving means for drawing the hardened steel wire through said guide in contact with but beneath and atright angles to the insulated wire passing thereover, a pivotally mounted'calibrated instant at which failure of the insulationjof said wire occurs. 1 r

2. A wire insulation abrasion resistance testing apparatus comprising'a reel upon which a supply of insulated wire to' be tested is coiled, variable speed wire engaging means for uncoiling said wire from said reel, adjustable braking means for op-' posing the uncoiling of said wire, wire abrading bar, a balance spring mounted at one end there of, a pressure roller mounted at the other, end of said bar adapted to engage the insulated wire in said guide, a weight slidably movable on said bar for progressively increasing the pressure on said pressure roller, a cord secured to said slidable weight and engaged by said driven stepped pulley, a slack take-up weight for said cord and means for indicating the instant at which failure of the insuiationof the test wire occurs.

'7. The method of testing the abrasion resistance qualities of an insulation on wire comprising means, means for slidably engaging said wire with said wire abrading means, pressure applying means for power driven progressively increasing the pressure between said wire and said wire abrading means, and means indicating the in-- stant at which failure of the insulation -of said wire occurs v 3-. A wire insulation abrasion resistance testing apparatus comprising a wire abrading means adapted to present continuously a fresh abrading surface, a speed adjustable wire engaging means for drawing a sample of insulated wire across said abrading surface, adjustable braking means for opposing movement of said wire thereover,

I ance qualities of an insulation on wire comprising passing the wire at a predetermined speed and '65,

calibrated power driven progressively increasing pressure applying means adapted-to press said wire against said abrading surface, and means indicating the instant at which failure of the insulation onsaid wire occurs.

passing. the wire at a predetermined speed and tension at right angles to and in contact with an unimpaired constantly moving abrading means,

applying pressure between said insulation and i said abrading means at a progressively increasing rate, and noting the pressure at whichfailure of I said insulation occurs.

8. The method of testing the abrasion resisttension through a guiding means at an angle to and in contact with an unimpaired constantly moving abrading means, applying pressure between said insulation and said ',abrading means at a progressively increasing rate, and noting the pressure at which failure of said insulation occurs.

9. A wire insulation abrasion resistance testing apparatus comprising a hardened steel insulation abrading wire, a guide through which said abrading wire is passed at a predetermined tension and speed, speed adjustable wire engaging means for drawing at a predetermined speeds sample of insuiatedwiretobetestedthroushsaidguideat 7 rlzhtanalestoandincontactwithsaidinsuiation abradin: wire, adjustable brakin: means tor opposing movement of said wire sample. pressure oisaidtest 10.'1hemethodo1testinthe abrasionresistance'qualities of an insulation on wire comprising passing the wire at'a predetermined speed and tension at an ansle to and in contact with anunimpaired constantly movins abrading means, applying pressure between said insulation and said sbrading means at a prolressivels increasing rate.

and noting the pressure at which failure of said insulation occurs.

' HAROLD K. GRAVES.

csm'mcs'rs or comcnon Patent no. 2,573,115.

HAROLD x; omwss.

A It is herehy certified that err-or appears in the printed specification oithe abo've nunberedpatent requiring correction as follows: Page 2, first column, line 59; claim 2,'str1ke out "pow er driven" andfineert the same before "pressure' in line 58, same claim; and thatthe said Letters Patent should be read with this correction therein that the same may conformto the record of the case in the Patent Office. I I

-- Signed andsealed this 26th day crime, A. D. 191.5.

(Seal) Leslie Frazer Acting Commissioner of Patents.

drawing at a predetermined speeds sample of insuiatedwiretobetestedthroushsaidguideat 7 rlzhtanalestoandincontactwithsaidinsuiation abradin: wire, adjustable brakin: means tor opposing movement of said wire sample. pressure oisaidtest 10.'1hemethodo1testinthe abrasionresistance'qualities of an insulation on wire comprising passing the wire at'a predetermined speed and tension at an ansle to and in contact with anunimpaired constantly movins abrading means, applying pressure between said insulation and said sbrading means at a prolressivels increasing rate.

and noting the pressure at which failure of said insulation occurs.

' HAROLD K. GRAVES.

csm'mcs'rs or comcnon Patent no. 2,573,115.

HAROLD x; omwss.

A It is herehy certified that err-or appears in the printed specification oithe abo've nunberedpatent requiring correction as follows: Page 2, first column, line 59; claim 2,'str1ke out "pow er driven" andfineert the same before "pressure' in line 58, same claim; and thatthe said Letters Patent should be read with this correction therein that the same may conformto the record of the case in the Patent Office. I I

-- Signed andsealed this 26th day crime, A. D. 191.5.

(Seal) Leslie Frazer Acting Commissioner of Patents. 

